Kyessayev O. The Water Treeing in Power Cables Under the Influence of a Strong Electric Field and Their Detection Technique.

Object of study: the process of aging of power cables with cross-linked polyethylene insulation of medium voltage of coaxial design with water-blocking barrier under the action of a strong electric field and moisture. Purpose: To substantiate the technique of detecting water treeings in medium-voltage power cables of a coaxial design with a water-blocking barrier under the action of a strong electric field. Research methods: High-frequency dielectric spectroscopy; Method of discrete resistive circuits for the replacement of inductance and capacitance; The method of nodal potentials in modeling the propagation of a pulse signal in a power cable with lumped irregularities. Theoretical and practical results: high-frequency dielectric spectroscopy of polymer insulation allows detecting the appearance of free moisture in power and radio-frequency cables; Pulse reflectometry in the time domain is a promising method for diagnosing operational heterogeneities in power cables. Novelty: Based on the dynamics of the change in the coefficients of pair correlation of absorption currents the criterion of the degree of humidity was proposed; The correlation between the relaxation maxima width of the dielectric loss and the dynamics of the insulation resistance changing during the moistening of power cables was established. Results: the results of dissertation are use on PJSC "Yuzhkabel", JSC "Plant "Eloks" and in studying process of the Department of cable technics NTU "KhPI". Scope of application: electrical and cable industry.